|Headquarters||Mountain View, California|
|Key people||Adam D'Angelo (CEO)|
|Alexa rank||713 (August 2012[update])|
|Type of site||Knowledge markets|
Quora is a question-and-answer website created, edited and organized by its community of users. The company was founded in June 2009, and the website was made available to the public on June 21, 2010.
Quora aggregates questions and answers to topics. Users can collaborate by editing questions and suggesting edits to other users' answers. Quora's main competitors are social bookmarking sites like reddit, social networking sites like ChaCha, and numerous question and answer websites.
Quora was co-founded by two former Facebook employees, Adam D'Angelo and Charlie Cheever. D'Angelo resigned from his position at Facebook in January 2010 to create Quora. He said that he and Cheever were inspired to create Quora because "we thought that Q & A is one of those areas on the Internet where there are a lot of sites, but no one had come along and built something that was really good yet." Quora's base of users grew quickly in December 2010.
Quora had an estimated 500,000 registered users, as of January 2011. In June 2011, Quora redesigned its website, in order to make information discovery and navigation easier. Some noted that the redesigned site had definite similarities to Wikipedia. Quora released an official iPhone app on September 29, 2011  and an official Android app on September 5, 2012.
Quora requires users to register with their real names rather than a screen name. Quora users may also link/ log-in with their Quora accounts with their Twitter and Facebook accounts. Quora users can upvote or downvote answers. They can also suggest edits to existing answers provided by other users. The Quora community includes some well-known people, such as Steve Case, Marc Andreesen, Dustin Moskovitz, Jimmy Wales, Justin Trudeau and Ashton Kutcher  The largest group of Quora users is located in Silicon Valley, followed by New York City. Almost 30% of its users are Indians as of February 2013.
Quora uses Pylons and Comet for its backend and Ubuntu Linux as its operating system with MySQL as its database. It also uses Git and memcached. Quora uses Nginx as a reverse proxy server and HAProxy for load balancing. Quora has developed its own algorithm for ranking answers, which works similar to PageRank. Quora uses Amazon Elastic Compute Cloud technology to host the servers that run its website. In August 2011, Quora switched its infrastructure's Python implementation from CPython to PyPy, in order to improve response time.
In August 2012, Blogger Ivan Kirigin pointed out that it was possible for acquaintances to see his activity including which questions he had looked at. By default, Quora exposes its users' profiles, including their personal names, to search engines.
In March 2010, Quora received funding in the amount of $11 million from Benchmark Capital, valuing the start-up at $86 million. Quora's valuation was rumored to be more than $1 billion in February 2011, and the privately held company possibly turned down an acquisition offer of $300 million, according to Business Insider.
In May 2012, Quora raised $50 million in Series B funds, valuing the company at over $400 million and bringing their total funding to $61 million. The co-founder D'Angelo, who owns 0.8% of Facebook stock, also invested $20 million of his own money in the B round. (same source)
According to Robert Scoble, Quora succeeded in combining attributes of Twitter, Facebook, Google Wave and similar websites that are based on a system of users voting up content. Scoble later criticized Quora for being a "horrid service for blogging," and although a decent question and answer website, not substantially better than competitors. The Daily Telegraph has predicted that Quora will become larger than Twitter. Quora, along with Airbnb and Dropbox, has been named among the next generation of multibillion dollar start-ups by the New York Times.
In 2010 D'Angelo and Cheever were among five named "Smartest Engineer runner-up" in the "smartest people in the tech" article by CNNMoney. They were also both listed in the Inc. Top 30 Under-30 entrepreneurs list of 2011.
Quora forces the use of their mobile app to browse it on mobile devices.
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